The naming of the SSL parameters was changed in version 2.4.1:
- ca_path has been changed to certpath
- The environment variable is not a documented way of modifying SSL settings
- Using lcb_cntl_string here is not going to work, since the SSL settings must be applied early on during handle creation, thus it must be set in the connection string.
See http://docs.couchbase.com/sdk-api/couchbase-c-client-2.4.2/group__lcb__initialization.html for more details.
Hope this helps.